Intake sealing and blocking the heat crossover

The Edelbrock Air-gap effectively acts as a valley pan. Oh...and Mopar has had air-gaps since the 50's V-8's, nothing new.

On my 318 with Weiand manifold I just cut some stainless sheet a little bigger than the opening and installed the manifold with gasket. That was maybe 8 years ago. As far as I know it's still working ok. My car is a little rough when cold and the blocked port may be a big part of that. Once the engine has warmed a little it's fine. Of course I don't drive it in the winter.